DUBLIN (CNS) — Irish bishops have warned that presenting same sex-partnerships as equivalent to marriage would be akin to saying that the union of man and woman is no longer the foundation of society.

In a pastoral statement aimed at presenting the church’s teaching on marriage ahead of a vote on same-sex marriage due to be held early next year, the Irish bishops’ conference said the promotion of the unique nature of marriage as a union between one man and one woman is a matter of justice.

“The Catholic Church, with other Christians and those of no particular religious view, regard the family based on marriage between a woman and a man as the single most important institution in any society,” said the statement issued Dec. 3 after the general meeting of the bishops’ conference in Maynooth.

“To seek to re-define the nature of marriage would be to undermine it as the fundamental building block of our society,” the bishops said.

The church’s intervention in the debate ahead of a constitutional referendum in early 2015 comes just a day after Prime Minister Enda Kenny attended a function in one of Dublin’s best-known gay bars. Kenny, who has pledged to work for a “yes” vote in a referendum that would permit same-sex couples to have civil marriages, attending an event hosted by the lesbian, gay, bisexual and transgender lobby within his Fine Gael party.

The bishops said the “church seeks with others to reaffirm the rational basis for holding that marriage should be reserved for the unique and complementary relationship between a woman and a man from which the generation and upbringing of children is uniquely possible.”

“This understanding of marriage is deeply rooted in all cultures: It is not intended to exclude or disadvantage anyone,” the statement added.

The statement said children “have a natural right to a mother and a father, and this is the best environment for them where possible. It is therefore deserving of special recognition and promotion by the state.”

The church leaders insist that “the debate at the core of the call for ‘same-sex marriage’ is not about equality or about the separation of a religious view of marriage from a civil view of marriage. It is about the very nature of marriage itself and the importance society places on the role of mothers and fathers in bringing up children.”

The bishops said they believed that legitimate rights can and should be afforded to same-sex couples “without sacrificing the institution of marriage and family and the fundamental role they play in society.”

The latest opinion poll indicates that an overwhelming majority of Irish people will vote to amend the constitution to legalize same-sex marriage.

No firm date has been set for the referendum, but the government has promised it will take place in the spring.